Atypical cutaneous cryptococcosis in cats

Cryptococcus is a fungus causing infection infections in humans and mammals including cats. In fact, it is the most common systemic fungus of cats worldwide. It usually affects the respiratory tract, in particular the nasal cavity and sinuses. It is less commonly associated with skin lesions. Typically, numerous organisms with a thick capsule are typically present microscopically, and are associated with mild dermatitis. The abundant organisms lend a classic “soap bubble” appearance to stained microscope slides of affected tissues.

These authors describe an unusual manifestation of infection in four cases. Grossly, lesions were primarily nodular or papular in nature with rare ulceration. Microscopically, there was severe inflammation involving eosinophils and rare Cryptococcus organisms lacking their capsules. These intralesional organisms were uncommon making them difficult to find on routine examination. The authors conclude that when severe inflammatory dermatitis is found without an identifiable cause, special testing for Cryptococcus organisms should be done. (MK)